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package org.openjdk.jmc.joverflow.heap.parser;

import org.openjdk.jmc.joverflow.heap.model.Snapshot;
import org.openjdk.jmc.joverflow.util.VerboseOutputCollector;

/**
 * Abstract base class for reading object dump files, with a static method that returns a concrete
 * implementation. One of the reasons that we don't simply provide a static method for reading a
 * snapshot, is that one can invoke HeapDumpReader.read(), and then call getProgressPercentage()
 * method on the same object periodically, to get an estimate of the reading progress. Dump reading
 * can be also cancelled via cancelReading() call.
 */
public abstract class HeapDumpReader {
	/** Read a snapshot from a data input stream. */
	abstract public Snapshot read() throws DumpCorruptedException, HprofParsingCancelledException;

	abstract public int getProgressPercentage();

	abstract public void cancelReading();

	/**
	 * Create a reader for a heap dump. An instance of ReadBuffer.Factory passed to this method
	 * defines the source of the dump (e.g. a file vs. a byte array), and any additional information
	 * about the dump.
	 */
	public static HeapDumpReader createReader(
		ReadBuffer.Factory bufFactory, int explicitPointerSize, VerboseOutputCollector vc)
			throws DumpCorruptedException {
		return new HprofReader(bufFactory, false, explicitPointerSize, vc);
	}

}
